Support the Arctic Sea Ice Forum and Blog

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - prokaryotes

Pages: [1]
1
Permafrost / Re: Arctic Methane Release
« on: July 13, 2019, 05:09:12 AM »
Made a new video. Soil layers of permafrost that scientists expected to remain frozen for at least 70 more years have already begun thawing.

<SNIPPAGE>


Excellent video Prokaryotes! I live on the boundary of continuous/discontinuous permafrost; monitoring retrogressive thaw slumps and living with warm permafrost is everyday life here. There are permafrosts dated to 400K BP here- and they are thawing.

2
Antarctica / Re: Thwaites Glacier Discussion
« on: June 22, 2019, 03:22:50 PM »
https://interactive.pri.org/2019/05/antarctica/submarine-glacier-tour.html

An AUV (autonomous underwater vehicle) was underneath the Thwaites ice shelf.

3
Arctic sea ice / Re: SMOS
« on: June 22, 2019, 12:24:40 AM »
I don't recall ever seeing the term "flaw polynya" before, and it took some searching to find a definition, finally (from here):
Quote
flaw polynyas (band-like ice-free areas), which form
simultaneously with land-fast ice in November. Flaw polynyas
reach tens of kilometres in width and migrate out of fast ice
hundreds of kilometres northward (Smolyanitsky et al., 2003),
and here
Quote
A polynya is defined as any nonlinear-shaped area of open water and/or sea ice cover < 30 cm thick enclosed by a much thicker ice cover (WMO 1970). It can be restricted on one side by a coast, terrned shore polynyas, or bounded by fast ice, termed flaw polynyas.

4
Consequences / Re: Drought 2019
« on: June 20, 2019, 10:38:21 PM »
Satellite Images of Parched Water Bodies Highlight Chennai Drought: Before & After
https://www.news18.com/photogallery/india/tamil-nadu-water-woes-before-after-satellite-photos-of-chennais-dry-lakes-2195293.html

https://www.9news.com.au/world/drought-chennai-indias-sixth-biggest-city-is-almost-entirely-out-of-water/fc504a1b-9da7-4508-a353-4c03089d07d2


Chembarambakkam Lake in Chennai before the drought. 2018

Chembarambakkam Lake in Chennai after the drought. 2019


Puzhal reservoir in Chennai before the drought 2018

Puzhal reservoir in Chennai after the drought 2019

6
The forum / Re: Arctic Sea Ice Forum Humor
« on: April 29, 2019, 08:22:20 PM »
https://twitter.com/Sustainable2050/status/1122727213168779266

"Climate change has two causes: human activity and human inactivity"



7
The linked reference indicates that the Beaufort Gyre halocline has been 'archiving' ocean heat for the past three decades.  When this warm water is eventually released, it will melt significant amounts of Arctic sea ice.

Mary-Louise Timmermans, John Toole and Richard Krishfield (29 Aug 2018), "Warming of the interior Arctic Ocean linked to sea ice losses at the basin margins", Science Advances , Vol. 4, no. 8, eaat6773, DOI: 10.1126/sciadv.aat6773

http://advances.sciencemag.org/content/4/8/eaat6773

Abstract: "Arctic Ocean measurements reveal a near doubling of ocean heat content relative to the freezing temperature in the Beaufort Gyre halocline over the past three decades (1987–2017). This warming is linked to anomalous solar heating of surface waters in the northern Chukchi Sea, a main entryway for halocline waters to join the interior Beaufort Gyre. Summer solar heat absorption by the surface waters has increased fivefold over the same time period, chiefly because of reduced sea ice coverage. It is shown that the solar heating, considered together with subduction rates of surface water in this region, is sufficient to account for the observed halocline warming. Heat absorption at the basin margins and its subsequent accumulation in the ocean interior, therefore, have consequences for Beaufort Gyre sea ice beyond the summer season."

See also:

Title: "‘Archived’ heat has reached deep into the Arctic interior, researchers say"

https://news.yale.edu/2018/08/29/archived-heat-has-reached-deep-arctic-interior-researchers-say

Extract: "“We document a striking ocean warming in one of the main basins of the interior Arctic Ocean, the Canadian Basin,” said lead author Mary-Louise Timmermans, a professor of geology and geophysics at Yale University.

The upper ocean in the Canadian Basin has seen a two-fold increase in heat content over the past 30 years, the researchers said. They traced the source to waters hundreds of miles to the south, where reduced sea ice has left the surface ocean more exposed to summer solar warming. In turn, Arctic winds are driving the warmer water north, but below the surface waters."

&

Title: "'Ticking Time Bomb' of Heated Ocean Discovered Hidden Under The Arctic"

https://www.sciencealert.com/ticking-time-bomb-hidden-heated-ocean-water-under-arctic-canada-basin-chukchi-sea

Extract: "New research has uncovered evidence of a vast reservoir of heated water building up underneath the Arctic Ocean and penetrating deep into the heart of the polar region, where it threatens to melt the ice frozen on top. And maybe a lot of it.

"We document a striking ocean warming in one of the main basins of the interior Arctic Ocean, the Canadian Basin," explains oceanographer Mary-Louise Timmermans from Yale University.
Timmermans and her team analysed temperature data on the Canada Basin taken over the last 30 years, and found that the amount of heat in the warmest part of the water had effectively doubled in the period 1987 to 2017."

Edit: See Reply #75 for other discussion about the Beaufort Gyre.

8
..
Is there a topic discussing Marine Ice Sheet Instability?

There is currently no individual thread devoted to Marine Ice Sheet Instability.  However, the are numerous threads in the Antarctic folder (including those linked below) that contain numerous posts on this complex topic:

https://forum.arctic-sea-ice.net/index.php/topic,85.0.html
https://forum.arctic-sea-ice.net/index.php/topic,21.0.html
https://forum.arctic-sea-ice.net/index.php/topic,72.0.html
https://forum.arctic-sea-ice.net/index.php/topic,130.0.html

Part of the problem is that models of Marine Ice Sheet Instability are so immature that it is difficult to comment on them without writing a PhD Dissertation each and every time.

9
From a Google search:
Thanks.

The following link provides interactive diagrams of ice mass loss from various regions of the Antarctic thru August 16, 2016:

https://data1.geo.tu-dresden.de/ais_gmb/

10
ps. can someone suggest a good open study on Marine ice cliff instability?
From a Google search:

Daniel F Martin1, Brent M Minchew2, Stephen F Price3 and Esmond G Ng1, (2018), "Modeling Marine Ice Cliff Instability: Higher resolution leads to lower impact", (1)Lawrence Berkeley National Laboratory, Berkeley, CA, United States, (2)Organization Not Listed, Washington, DC, United States, (3)Los Alamos National Laboratory, Los Alamos, NM, United States

https://agu.confex.com/agu/fm18/preliminaryview.cgi/Paper435681.html

&

Jeremy N Bassis1, Doug Benn2 and Brandon Robert Berg1, (2018), "Anatomy of the Marine Ice Cliff Instability", (1)University of Michigan Ann Arbor, Ann Arbor, MI, United States, (2)University of St Andrews, Dept. of Geography and Sustainable Development, St Andrews, United Kingdom

https://agu.confex.com/agu/fm18/preliminaryview.cgi/Paper436995.html

&

Frank Pattyn (2018), "The paradigm shift in Antarctic ice sheet modelling", Nature Communications, volume 9, Article number: 2728, DOI: https://doi.org/10.1038/s41467-018-05003-z


https://www.nature.com/articles/s41467-018-05003-z

11
Arctic sea ice / Re: Arctic Image of the Day
« on: August 29, 2018, 12:32:39 AM »
The hazards of research near the pole.


12
Arctic sea ice / Re: What's new in the Arctic ?
« on: August 20, 2018, 10:38:26 AM »
A very interesting paper in Nature on sudden thawing of permafrost under thermokarst lakes.

Quote
Abstract

Permafrost carbon feedback (PCF) modeling has focused on gradual thaw of near-surface permafrost leading to enhanced carbon dioxide and methane emissions that accelerate global climate warming. These state-of-the-art land models have yet to incorporate deeper, abrupt thaw in the PCF. Here we use model data, supported by field observations, radiocarbon dating, and remote sensing, to show that methane and carbon dioxide emissions from abrupt thaw beneath thermokarst lakes will more than double radiative forcing from circumpolar permafrost-soil carbon fluxes this century. Abrupt thaw lake emissions are similar under moderate and high representative concentration pathways (RCP4.5 and RCP8.5), but their relative contribution to the PCF is much larger under the moderate warming scenario. Abrupt thaw accelerates mobilization of deeply frozen, ancient carbon, increasing 14C-depleted permafrost soil carbon emissions by ~125–190% compared to gradual thaw alone. These findings demonstrate the need to incorporate abrupt thaw processes in earth system models for more comprehensive projection of the PCF this century.

Quote
Abrupt thaw implications

While the cumulative land area subject to abrupt thaw lake formation is less than one tenth of permafrost land areas (Supplementary Fig. 4e, f), our modeling results (Fig. 4), supported by field work (Figs 1 and 5) and remote sensing (Fig. 3), show that an increase in the volume of newly thawed sub-lake sediments through expansion of existing and formation of new thermokarst lakes is likely to yield disproportionately large releases of 14C-depleted permafrost carbon to the atmosphere this century.

...

In contrast to shallow, gradual thaw that may rapidly re-form permafrost upon climate cooling, deep, CH4-yielding abrupt thaw is irreversible this century. Once formed, lake taliks continue to deepen even under colder climates17, mobilizing carbon that was sequestered from the atmosphere over tens of thousands of years. The release of this carbon as CH4 and CO2 is irreversible in the 21st century. This irreversible, abrupt thaw climate feedback is large enough to warrant continued efforts toward integrating mechanisms that speed up deep permafrost-carbon thaw and release into large-scale models used to predict the rate of Earth’s climate change.

13
Arctic sea ice / Re: Arctic Image of the Day
« on: July 27, 2018, 09:36:08 AM »
Another sample of Cave Art here from Frederikshåb Isblink:

14
Arctic sea ice / Re: Arctic Image of the Day
« on: July 23, 2018, 09:13:27 AM »


This phytoplankton bloom is in the Baltic.

15
Arctic sea ice / Re: Arctic Image of the Day
« on: July 05, 2018, 09:54:13 PM »
Those are clouds formed from Lee Waves

Thanks.  I looked them up.  Fascinating!  Like air in a wind instrument, only gravity-assisted.

16
Any comments?

Geoff,

I enjoyed watching the short video, as it offers a nice summary in a manner that the general public can digest.  Regarding Tamsin Edwards' criticism, I would say that it is irrelevant whether we know, as a proven fact, that human activity has caused the Amundsen Sea Embayment, ASE, marine glaciers to cross their tipping points, as climate models combined with field observation make an almost certain fact.  For example:

1. Proistosescu & Huybers (2017) demonstrate convincingly that since 1750 anthropogenic activity has slowly been increasing the heat content of both the Tropical Pacific Ocean and the Southern Ocean; which not only increases ocean driving ice mass loss from West Antarctic marine glaciers, but also has activated a slow-response positive feedback mechanism that is currently increasing ECS to at least the upper end of the AR5 range.

Cristian Proistosescu and Peter J. Huybers (05 Jul 2017), "Slow climate mode reconciles historical and model-based estimates of climate sensitivity", Science Advances, Vol. 3, no. 7, e1602821, DOI: 10.1126/sciadv.1602821

http://advances.sciencemag.org/content/3/7/e1602821

Thus, not only are humans responsible for increasing the heat content of the Southern Ocean but the associated increase of the current ECS value means that the hydrofracturing mechanism described by DeConto & Pollard could begin as soon as 2040; which would greatly accelerate ice mass loss from all of the WAIS.

2.  There is no serious doubt that human activity caused the ozone hole over Antarctica, which accelerated the westerly wind velocities into a 'sweet spot' for promoting the increased upwelling of relatively warm circumpolar deepwater, CDW, onto the continental shelves that lead to key marine glaciers in the ASE (and other Antarctic marine glaciers).  Thus not only are we responsible for increasing the heat content of the CDW, but we are responsible for the mechanism that delivers this heat content to the grounding line of key marine glaciers.

3.  It is my opinion that human activity has accelerated surface ice mass loss from Greenland (including due to both decreased albedo from air pollution and from increased surface temperatures), which most likely caused a 'cold spot' in the North Atlantic, which most likely has somewhat slowed the Meridional Overturning Circulation, MOC.  Hansen et al (2016) indicates that this slowing of the MOC has reduced the formation of polynas in the Weddell Sea area, which has promoted an increase in Antarctic sea ice area, which has protected the upwelled CDW from cooling as much as it use to; which promotes grounding line retreat of key Antarctic marine glaciers.  This bipolar seesaw action contributes to Hansen's ice-climate feedback which further increases ECS and which further increases the risk of hydrofracturing of key ASE marine glaciers circa 2040.

I could go on, but my main point is that reticent scientists do not hesitate to dream-up any highly improbably scenario (like SSP1) to indicate that we may never cross the 2C limit; but then they do not hesitate to imply that much more probable scenarios that lead to GMSTAs approaching at least 2.7C (at which point DeConto & Pollard's ice cliff and hydrofracturing mechanisms kick into high gear) are not absolutely proven and thus do not merit serious consideration by busy decision makers who are bedeviled by other fat-tailed risks.  Such a reticent scientific posture is not good science.

Best,
ASLR


17
Policy and solutions / US Military Basing and Climate Change
« on: April 07, 2015, 06:47:34 AM »
It's personal when I've spent time at the 5 most vulnerable, to Climate Change, US Military Facilities in the world!!


                Diego Garcia Atoll, IndianOcean

I just happened upon the following report by Catherine Foley, Adjunct Fellow at the American Security Project, in 2012: https://www.americansecurityproject.org/wp-content/uploads/2012/11/Military-Basing-and-Climate-Change.pdf

While this report certainly highlights the threats of Climate Change to US military infrastructure worldwide, what hit me very personally was that I have spent much time during my career at each one of the 5 facilities considered most vulnerable to Climate Change. What incenses me most is that the "War Hawks" in the US Congress who must depend on these facilities for further military campaigns of US Agression seem to claim that Climate Change is a Hoax! 

Below are a few quotes from the  report, then I will follow with  selected quotes about the 5  most vulnerable US military facilities followed by my personal experiences and observations:

Quote
Climate change not only affects our security through its impacts on the economy and our
physical infrastructure (roads, bridges, airports, etc.); it also can also affect domestic and
international military bases as flooding, drought and extreme weather events intensify.
Physical changes to the environment may disrupt U.S. military capabilities and facilities,
such as military training ranges or bases.

According to the U.S. Department of Defense (DoD) 2010 Quadrennial Defense Review,
there are a number of US military installations that are already at risk. The report says:

Quote
“In 2008, the National Intelligence Council [NIC] judged that more than 30 U.S. military
installations were already facing elevated levels of risk from rising sea levels. DoD’s operational
readiness hinges on continued access to land, air, and sea training and test space.”

Although sea-level rise is a major concern, other environmental threats must be taken into
consideration in order to keep our military installments safe and secure. We tend to look at
environmental threats on an individual, case-by-case basis, which does not take the plethora
of threats into account.

The 5 Most Vulnerable US Facilities in he order depicted in the article:

1.  Diego Garcia

On my first of 4 visits to Diego Garcia en route to/from US Battlegroups deployed in the Indian Ocean, I  thought Diego Garcia was the most beautiful island I'd ever seen. Nothing more beautiful than a sunrise through the windstrept  trees along the miles of pristine beaches.  On a subsequent visit, while enjoying the camaraderie of the Officers Club, I became a charter member of the Diego Garcia Yacht Club although my only previous experience on a sailboat was a small "sunfish" in a protected harbor in the Persian Gulf. 

Quote
Diego Garcia is a critical logistics hub for the US and UK militaries in the Middle East. However, the island is a coral atoll encompassing 67 square miles, of which only 10 square miles is dry land........The highest point above sea-level is 22 feet, but the island’s mean height above sea-level is 4 feet.........A sea level rise of a several feet would force the US military to undertake a costly and difficult military relocation process; in addition, the military would lose a
geographically strategic outpost in the Indian region.

2. Bahrain.

I spent many nights in Bahrain during Gulf War I (Operations Desert Shield and Desert Storm).  I loved the friendly locals and enjoyed visiting many of the historic sites, some of which predated the  Islamic era.

Quote
Military installations out of Bahrain, including U.S. “floating bases”- The U.S. military has built up military reinforcements into the Persian Gulf, many based out of Bahrain, to deter Iranian military from any possible attempt to shut the Strait of Hormuz (a key oil shipping route for the U.S.).

3. Guam.

I've only been there twice.  However, in addition to being strategically vital to the US, it is a major destination for Japanese "newlyweds" on their company sponsored honeymoons.

Quote
The military installation on the island of Guam is one of the most strategically important US bases in the Western Pacific Ocean. Military presence on Guam allows the US access to China and the rest of East Asia by air and sea to the West and Hawaii and North America to the East.9

4. Eglin AFB, Florida.

Quote
Located on the Gulf of Mexico, Eglin Air Force Base is the largest Air Force base in the world. It encompasses 724 square miles of land and occupies the majority of the northwest Florida panhandle. It serves as the focal point for all Air Force armaments and is home to the Air Force Armament Center (AAC), one of three product centers in the Air Force Material Command.
The AAC develops, tests and deploys many critical air-delivered weapons. It is a very important base not only for the US military but also for the local Florida economy. Since it is located on the coast in the Gulf of Mexico, it faces storm surges, sea-level rise and saltwater infiltration, which causes problems with freshwater resources in the area. With the increase of extreme weather, Eglin Air Force Base may face costly damages in the future

One of the few times I had to work with the Air Force, in my last over 30 years in the Defense Industry, was when I had  the opportunity to take a prototype Air-to-Air missile through all the final test protocols for the Air Force at Eglin AFB.  Since retirement I've enjoyed going back to the area to enjoy the  seafood and am hoping to be back there in a few weeks to do some fishing.

5. Norfolk Naval Base, VA.

Quote
Naval Base Norfolk is one of the largest naval complexes in the world, situated on the southern coast of Virginia in an area commonly known as Hampton Roads. The Naval Station houses US Atlantic Fleet, Commander Navy Region Mid-Atlantic and the Navy’s largest supply center.

The nearby Newport News shipyard is also the only yard in the U.S. that builds aircraft
carriers. Because of its location on the southern tip of Virginia, it is at risk of sea-level rise and storm surge, but it may also face threats from hurricanes in the Atlantic.

As the effects of climate change become more pronounced, Norfolk Naval Air Station may be effected more acutely, putting strategic naval resources at risk.

I can't begin to enumerate the number of times I've worked on naval vessels in the Norfolk area, be it Little Creek, Norfolk, Newport News, Portsmouth or Dam Neck (Training  Center).  Not only was that US Navy vessels it also included a number of Royal Saudi Navy vessels during a major expansion program in the early 80s. The US Navy is already constructing Double-decker piers at the Norfolk Naval Station in anticipation of predicted elevated sea levels, in spite of concerns by members of the GOP Congressional Delegation that AGW/CC is a hoax.

In Conclusion

My engineering expertise, in technical terms, was mostly related to shipboard anti-missile radar performance in varying electromagnetic, sea clutter, land clutter and battle group environments. My real-world experience with naval warfare is in the Persian Gulf.  I understand the threats, I know the concerns of naval commanders related to threats to our forces due to the current  escalation of tensions in the Middle East.

As an American, Vietnam veteran and an on sight-observer of Gulf War I, I am embarrassed  my countries elected officials lack of concern for the known impacts of AGW/CC on National Security and the associated critical infrastructure.














c

18
Antarctica / Discussion of WAIS Collapse Main Period from 2060 to 2100
« on: March 03, 2013, 02:55:49 AM »
Due to complexity of a hazard analysis for the potential abrupt collapse (either partial of full) of the WAIS, I have made many posts already, and for the sake of brevity I will try not to repeat the information/postulations presented in the "Potential Collapse" thread, nor the final SLR projections presented in the "Philosophical" thread.  While my hazard analysis for RCP 8.5 50% CL forcing is quite aggressive, projecting a eustatic SLR of about 0.5m for the period from 2000 to 2060 (and about 1m of SLR by 2060 for the 95% CL scenario); my SLR projections for my "collapse main period" are more aggressive still, estimating about 3m of eustatic SLR by 2100 for the RCP 8.5 50% CL case, and just over 5m of SLR by 2100 for the RCP 8.5 95% CL case.  Nevertheless, I hope that the supporting information presented in this thread clarifies the nature and probability of the "Collapse Main Period this Century" from 2060 to 2100.

I will start this "clarification" by providing the first accompanying figure (not previously posted in the "Collapse" thread) showing a plan view of the my RCP 8.5 50% CL scenario estimates of WAIS areas that may have experienced grounding line retreat by 2070.  This figure indicates several significant areas of proposed grounding line retreat including:
(a) the transparent orange area with Jakobshavn Effect acceleration and associated "ice melange" discussed extensively in the thread on the PIG/Thwaites system behavior up to 2060 show the two significant changes: (i) the Eastern trough ice stream has continued to exhibit "Jakobshavn Effect" acceleration behavior and the grounding line retreat for this ice stream has extended about an additional 200km in 10 years, while the grounding line retreat for the Western trough ice stream is proposed to slow dramatically as the seafloor becomes rough at the western end of this trough; and (ii) with the extension of the Western trough ice stream slowed, this allows for the extension of the grounding line retreat in the Southernly direction into several different branching troughs in this direction at a slower rate than for Eastern trough ice stream.
(b) the Ferrigno Subglacial cavity showed marked rate of extension driven largely by advection associate with relatively high CDW in the Bellingshausen Sea (with no Jakobshavn Effect), while the PIG subglacial cavity extension (ie groundling line retreat) remains slow due to rough seafloor conditions.
(c) The grounding line retreat for the Siple Coast ice stream accelerates as the Ross Ice Shelf is assumed to provide rapidly degrading buttressing support.
(d) The Weddell Sea Embayment, WSE, glaciers show a major surge of grounding line retreat due both to a projected re-direction of advective warm CDW into the WSE (below the Filchner-Ronne Ice Shelf), and due to ideal seafloor conditions (in the area of indicated grounding line retreat) to support the classic gravitationally driven marine ice sheet retreat behavior addressed in the second accompanying figure).  I will discuss the WSE proposed surge of grounding line retreat (by 2070) in the next post.

Pages: [1]